Blade



Dec. 10, 1929. m- 1,738,912

BLADE Filed Jan. 21, 1928 i INVENTOR.

357m. Laws.

ATTORNEY.

Patented Dec. '10,

UNITED STATES JOHN HILTON LUERS, O1 -DETBOIT, MICHIGAN BLADE Application filed January 21, 1928. Serial R0. 248,458.

This invention relates to improvements in 7 blades, or cutters, intended for use in lathes, automatic machines, and the like. It is an object of the invention to provide a blade for a such purposes as parting that will only require re-grindin at very infrequent intervals. Another ject of the invention is to provide a blade so constructed that the work may be rotated with a minimum amount of o power when cuts are being made, and wherein all tendency for the sides of the blade to bind against the cut sides of-the work is eliminated even as the cutting edge becomes dull, or it the blade is set slightly out of alignto meat.

With these and other objects in view which will be mentioned as the specification roceeds, the invention is hereinafter more ully described with the aid of the accompanying drawings, in which:

Figure 1 illustrates a side elevation of the invention, and

Figure 2 is an end view thereof.

The blade 1 consists of a wider upper portion 2 and a narrower lower portion 3, the sides of which latter are preferably parallel with one another. The cutting surface 4 of the blade'is hollow ground, or concave, and so shaped that its edges 4" both project upwards a substantially equal amount. The sides 6 of the upper portion 2 are also hollow ground, or concave, but their concavities are preferably described from centres 7 horizontally on a plane with the lower ends of these concave portions, so that the lower edges 6' of the sides 6 are nearer to ether than the upper edges of their sides w ich terminate at the edges 4 of the cutting surface 4. Moreover, the length of the hollow ground sides 6 is usually substantially no greater than the width of the cutting surface 4, and frequently less than the width of the said cutting surface, so that the radii between the centres 7 and the sides 6 are sufficiently short to provide greater clearance immediately un der the edges 4 than would normally be obtained by tapering these :sides unless they were tapered at an unusual and excessive angle which, if continued, would tend to weaken the whole blade.

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The width of the lower portion 3 of the blade is preferably slightly less than the distance between the edges 6.

The purpose of hollow grinding the sides 6 is to provide clearance for the sides of the blade particularly when the edges of the cutting surface wear. In this way frictional contact between the sides of the cutter and the sides of the cut in the work is very ma terially lessened. Again if the blade is so to set that it leans slightly to one side, as not infrequently happens, the side of the blade, when hollow ground, clears the work whereas a flat or wedge-shaped blade would bind.

Having thus described myinvention what l to desire to secure by Letters Patent is l. A blade having a wider and a narrower portion, said wider portion having a cutting edge across its outer margin and hollow ground sides which are widerapart at their to outer ends, and the sides of said narrower portion being substantially parallel with one another and a lesser distance apart than any opposed portions of said hollow ground sides.

2. A blade having a wider and a narrower it portion, said wider portion having a cutting surface across its outer margin and hollow ground sides, the centres from which said hollow ground sides are described being substantially on the same plane as the inner ends so of said sides.

3. A blade having a wider and a narrower portion, said wider portion having a cutting surface across its outer margin and hollow ground sides, said sides being substantially to no longer than the width of said cutting surface and further apart at their outer ends than at their ends adjacent to said narrower portion and said narrower portion being materially'lon er than said wider ortion.

4.- A bla e having a wider an a narrower portion, said wider portion havin a hollow groundouter surface oneend of w rich forms a cutting surface, said wider portion having hollow ground sides widest apart at their outer ends, and the-narrower portion havin its sides nearer together than any oppose portions of said hollow ground sides.

5. A blade having a wider and a narrower portion, said wider portion having a hollow mo a with a relatively broad, thin shank and a cuttin head, said cuttin head having at least t ree hollow groun surfaces, two of which areopposite each other, and the base of the head next to the shank being of less over-all width than the over-all width of the opposite or cuttin surface thereof.

Join: MILTON LUERS. 

